WASHINGTON (Reuters) — President Barack
Obama brought congressional leaders to the White House on Thursday for
talks on the Ukraine crisis, with diplomatic efforts between the United
States and Russia facing a hard slog.

A week after a trip to Europe that was dominated by meetings to
discuss ways to react to Russia's annexation of Crimea, Obama sat
down with Democratic and Republican leaders of the U.S. Senate and
the House of Representatives.

Obama last spoke to Russian President Vladimir Putin on Friday by
telephone. Since then, U.S. Secretary of State John Kerry has
engaged in discussions with his Russian counterpart, Sergei Lavrov,
about a diplomatic outcome to the dispute.

But no such resolution has presented itself, and Russia has shown no
sign of loosening its grip on Crimea in what Moscow says is an
effort to ensure the safety of ethnic Russians in the region.

Obama and European leaders agreed last week to impose sanctions
against targeted sectors of the Russian economy, like its energy
industry, should the Russian military move deeper into Ukraine.

The allies are also discussing ways to bolster NATO and increase the
allied presence in member nations near Russia like the Baltic states
of Latvia, Lithuania and Estonia.

A White House official said Obama and Vice President Joe Biden met
with the two top Democrats in Washington, Senate Majority Leader
Harry Reid and House Minority Leader Nancy Pelosi, and their
Republican counterparts, House Speaker John Boehner and Senate
Minority Leader Mitch McConnell.

Obama told them that "the United States continues to lead a
coordinated international effort to support Ukraine and isolate
Russia for its violation of Ukraine's sovereignty and territorial
integrity," the White House official said.

Earlier on Thursday, Obama signed legislation passed earlier in the
week by Congress to provide $1 billion in loan guarantees for the
cash-strapped Ukraine government.

The White House official said Obama also discussed with the
congressional leaders his participation in a nuclear security summit
in Brussels and his talks with Pope Francis at the Vatican and with
Saudi Arabia's King Abdullah near Riyadh.

But with Ukraine as the central foreign policy challenge in recent
weeks, most of the more than hourlong meeting was about the
standoff with Russia.

White House spokesman Jay Carney, at his daily news briefing,
objected to Russia's increase in natural gas prices for Ukraine and
said markets should determine prices.

He spoke after Russian natural gas producer Gazprom announced it
would virtually double the gas price for Urkraine to $485 per 1,000
cubic meters this month, which Ukraine said was politically
motivated.

"That kind of action taken coercively against Ukraine is something
we oppose," Carney told reporters.